A device of this kind is known from United States Patent Application Publication No. 2016/0311624. In this known arrangement, the removal device comprises at least one conveying worm, with each conveying worm working individually. In particular in the case of grainy material, however, it may occur that the material taken up by the conveying worm during the upward movement of the swivel frame receiving the conveying worm at least partially falls through the gap between the individual volutions and that such material at least partially dodges during the subsequent return swivelling movement of the swivel frame of the conveying worm received by the latter. A discharge process for entirely discharging the dirt removal container may thus be rather time-consuming. The known removal device, therefore, does not operate sufficiently efficient.